Improvement in elastic attachments to rocking-chairs



J. BEIBRSDORP 1L-W. I. BUNKER. Elastic Attachments to Rocking-Chairs.

No. 214,871. Patented April 29,1879.

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UNITED STATES PATENT OEEICE JACOB BEIERSDORF AND WILLIAM I. BUNKER, OF-CHICAGO, ILLINOIS.

IMPROVEMENT IN ELASTIC ATTACHMENTS TO ROCKING-CHAIRS.

Specification forming part of Letters Patent No. 214,871, dated April29, 1879; application filed February 24, 1879.

To all whom it may concern Be it known that we, JAooB BEIEEsDoRF andWILLIAM I. BUNKER, both of Chicago, in the county of Cook and State ofIllinois, have invented a new and Improved Elastic Attachment toRocking-Chairs; and that the following is a full, clear, and exactdescription thereof, reference being had to the accompanying drawings7forming part of this specification.

This invention relates to an attachment for that class of chairs inwhich the rockin g-frame rests upon a base or supporting frame; and itis our object to provide such an attachment which will not only hold therocker centrally on its base, but also will yield to and facilitate therocking movements of the chair.

Our invention therein consists in inclosing the spring in a rubber tubeof the same length as the spring, and presenting a smooth surface whenthe spring is not extended; in a spring-connection consisting of theforegoing elements and a cord within the spring secured to the bosses ofthe brackets; and, further, in

. the combination, with the brackets and spring,

of an auxiliary C-spring connecting the brackets, for adj ustablyresisting and controlling the rocking movements of the chair, all asfully hereinafter explained.

In the drawings, Figure l represents an elevation of our improved springas attached to the rocker and base of a chair, and Fig. 2 represents atransverse vertical section of the same.

Like letters in the several figures of the drawings indicate like parts.

.A designates a portion of the base-frame, and B of the rocking-frame ofa chair, both of which are constructed in the usual manner.'

C C are the brackets or iixtures, shaped exactly alike, one of which7with wood-screws, is secured against the inward face of the base, andthe other. against the inward face of the rocker. Each bracket Cconsists of a plate having a ilangc rectangular therewith, by which itis secured against the base or rocker, and a boss, c, which is providedwith a spiral half-round groove on its exterior surface, correspondingwith the internal diameter and the spiral coils of spring D, so as to bescrewed into the ends of the same, and form a stiff and rigid connectiontherewith. This spring D is made of steel or brass wire, wound upon acylindrical mandrel in such a manner that its several coils will besuccessively in close proximity with each other, and a piece of rubberhose or tubing, d, is placed over this spring, with its endssufficiently projecting over the ends of said spring to be bound andconcealed by rubber rings e. Heretofore, in attachments for a likepurpose, the spiral springs have been pivotally connected by having aloop or hook formed to each end, and therefore only were adapted forlongitudinal yield, and not for holding the rocker centrally upon itsbase, allowing the same to slide back and forward with each rockingmotion, and necessitating an additional contrivance as a preventive forsuch slip.

Withour above-described device for securing the ends of such springsrigidly upon the `brackets each rocking movement of the chair will notonly expand the springs longitudinally, but will also deilect the samemore or less, so as to attain a curved form in the direction towardwhich the chair rcclines, and thus by its flexible elasticity resistsdeviation of the rocker from its central position.

The rubber covering, without impeding the elastic properties of thespring, will protect the same from external iniluences, such as promotecorrosion, and. will make the actions of the spring noiseless.

As a provision against injury to the springs D by too great expansion,we connect the two brackets G C with a slack wire cord or chain, g,secured with its ends in any suitable manner to the bosses c, so as tobe concealed in the spring, and receiving the strain after the limit ofsuch safe expansion has been reached.

Each bracket C may be provided with a socket, h, for receiving the endsof a C-shaped wire spring, I, having one or several coils, i, formed toits middle. This spring, by being placed over the brackets G, willfurnish additional resistance to the longitudinal expansion of spring Dand to its lateral movement, so as to allow the chair to rock only inthe direction toward the said spring I, which may be turned to point toeither end of the chair, and thus furnish the mea-ns for controlling.;`the rocking movements ofthe same, to be more or less on the recline ineither direction.

Besides the advantages of our elastic attachment already pointed out, onaccount of its great simplicity, itis cheap to manufacture, is durable,and complete in itself, ready to be secured to the chair and base.

We do not wish to be confined tothe device herein described oi' securingthe ends oi' the spring to the brackets by providing' the latter withspirallygrooved bosses, as any other device of fastening which willbring about a stiii and rigid connection will answer the same purpose.

What We claim as our invention is 1. The combination, with the base androcker of a chair, of a spiral spring secured at its ends to said baseand rocker, and a tiexble rubber tube inclosing; the spring, the saidtube being I of the same length as the spring, being extended With thespring, and presenting a smooth surface when the spring is not extended,substantially as described and shown.

L. The combination, with the base A and rocker B of a rocking-chairprovided with brackets C, having spiral1ygrooved bosses c, of the spiralspring D, turned onto the said bosses, the inelosing rubber tube d, andthe cord g, connecting the bosses, substantially as described and shown.

3. In combination with the elastic attachment to a rocking-chaircomposed of brackets C and spring I), substantially in the manner setforth, the auxiliary spring I, constructed as described, and operatingas and for the purpose specified.

JACOB BEIERSDORF. WILLIAM I. BUNKER.

Witnesses z )MIL H FROMMANN, Gsm FROMMANN.

